The minute hand of a clock is 15 cm long. Calculate the area swept by it in 20 minutes.

Given:

Length of minute hand = 15 cm

Here, the length of the minute hand is equal to the radius of the sector formed by the minute hand.

Angle made by the minute hand in 1 minute = = 6°

Angle made by the minute hand in 20 minutes = 20 × 6 = 120°

Here, the area swept by the minute hand is equal to the area of the corresponding sector made.

∵ Area of sector = × πr²

= × 3.14 × 15 × 15 = 235.5 cm²

Hence, the area swept by it in 20 minutes is 235.5 cm².